Snapshotting for rollback after updates was[ Re: Drawing lessons from fatal SELinux bug #1054350]

Reindl Harald h.reindl at
Sun Jan 26 20:07:54 UTC 2014

Am 26.01.2014 20:56, schrieb Chris Murphy:
>> What about mail application change the format of the mail folders ?
> Good question because I experienced this recently. So the way Apple does this on OS X with Mail, 
> there is no such thing as a mail format change during the life of a major OS version. So major 
> OS versions are 10.7, 10.8, and now 10.9

and you have a warranty for that?

> So it's impossible the mail format would change between 10.7.1 and 10.7.2 in such a way that 10.7.2 
> mail could not be read by the 10.7.1 or 10.7.0 mail application

and you have a warranty for that?
no you do *not*

> I can upgrade and downgrade all along 10.7.x and the file format is the same.

you *think* that

> Recently I learned that there are two mail formats. There's the every day used format that 
> is apparently completely incompatible between major versions of Mail
> I can export 10.8 Mail in this format, and 10.7 Mail can also read it. And even this pissed 
> me off as well as several thousand users (at least) based on Apple's community forums on the 
> subject because most of us expect to be able to directly import 10.7 mail into 10.8 Mail. 

where you prove that what you said above is wrong

> Well, the mail servers regularly get updated by the company I pay for such things, and I've 
> never noticed the change. It uses IMAP so I don't think the server even cares, its just a bunch 
> of folders and files

blabla - nobody talks about the mailserver

the topic is *internal* data of *local* software
you may have luck and nothing happens

with bad luck you even won't realize that there are new mails you never face
because of happy upgrade/downgrade internal caches are accessed with
*undefined bahvior*

any software on that planet will recognize upgrades and convert *internal* data
but nobody will give you a warranty how the same software behaves after a downgrade

yes, in most cases nothing bad happens
in rare cases you recognize the problem and find a solution
in some cases you even don't recognize that internal things are slightly going wrong

-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 246 bytes
Desc: OpenPGP digital signature
URL: <>

More information about the devel mailing list